The paper analyses the results of interaction between suicide operatives and\ud bystanders in the course of 103 suicide attacks in Israel over a recent threeyear\ud period. It shows that bystanders’ intervention tended to reduce the\ud casualties arising by numbers that were both statistically and practically\ud significant. When bystanders intervened, however, this was often at the cost of\ud their own lives. The value of a challenge was particularly large for suicide\ud missions associated with Hamas, but Hamas operations were also less likely to\ud meet a challenge in the first place. These findings, while preliminary, may\ud have implications for counter-terrorism. More systematic collection of\ud statistical data relating to suicide incidents would be of benefit.